Venom injected by the insect contains
inflammatory substances that cause local
pain, redness, and swelling for about 48
hours. Any sting in the mouth or throat
is dangerous because the swelling may
obstruct breathing. About 1 person in 200
is allergic to insect venom, and a severe
allergic reaction can occur, leading to
anaphylactic shock. A procedure known
as hyposensitizationis sometimes rec-
ommended for such people.
If the symptoms of anaphylactic shock
develop, it is essential to seek emergency
medical treatment. Any person who is
known to be hypersensitive to bee or
wasp venom should obtain and carry an
emergency kit for the self-injection of
adrenaline(epinephrine).
insecurityLack of self-confidence and
uncertainty about one’s abilities, aims,
and relationships with others. A feeling
of insecurity may be a feature of anxiety
and other neurotic mental disorders.
insightBeing aware of one’s own men-
tal state. In a general sense, this means
knowing one’s own strengths, weak-
nesses, and abilities. The term also has
the specific psychiatric meaning of
knowing that one’s symptoms are an ill-
ness. Loss of insight may be a feature of
psychotic and neurotic disorders.
in situA Latin term meaning “in place”.
The phrase “carcinoma in situ” is used
to describe tissue (particularly of the
skin or cervix) that is cancerous only in
its surface cells.
insomniaDifficulty in falling asleep or
in staying asleep. About 1 in 3 adults
suffer from insomnia at some time in
their lives. The most common cause is
worry, but other causes include physical
symptoms such as a cough or itching or
conditions such as restless legs. Environ-
mental and lifestyle factors or misuse of
sleeping drugsare also common causes.
Insomnia can also be a symptom of a
psychiatric illness, such as anxietyand/
or depression. Withdrawal symptoms
from antidepressants, antianxiety drugs,
sleeping drugs, and some illicit drugs
(see drug abuse), may cause insomnia.
instinctAn innate primitive urge. The
need for warmth, food, love, and sex are
all forms of instinct, but the instinct for
survival is probably the most powerful.
institutionalizationLoss of personal
independence that stems from living for
long periods under a rigid regime, such
as in a prison or other large institution.
Apathy, obeying orders unquestioningly,
accepting a standard routine, and loss
of interests are the main features.
insulinA hormone produced by the pan-
creasthat regulates glucoselevels in the
blood. It is normally produced in re-
sponse to raised glucose levels following
a meal and promotes glucose absorption
into the liverand muscle cells (where it is
converted into energy). Insulin thus pre-
vents a build-up of glucose and ensures
that tissues have sufficient amounts of
glucose. Failure of insulin production
results in diabetes mellitus. An insulinoma
is a rare tumour that causes excessive
production of insulin and consequent
attacks of hypoglycaemia.
Insulin replacement, self-administered
by injection or through an infusion
pump (see pump, insulin), is used in the
treatment of diabetes mellitus. Insulin
cannot be taken orally because it is
destroyed by stomach acid. Prepara-
tions are produced from pig or ox
pancreas or, more commonly, by genetic
engineering. This treatment prevents
excessively high glucose levels in blood
(hyperglycaemia) and ketosis(a build-
up of certain acids in the blood), which,
in severe cases, may cause coma.
Too high a dose of insulin will cause
hypoglycaemia, which can be relieved by
consuming food or a sugary drink. Severe
hypoglycaemia may cause coma, for which
emergency treatment with an injection of
glucose or glucagon(a hormone that op-
poses the effects of insulin) is necessary.
insulinomaA rare noncancerous tumour
of the insulin-producing cells of the pan-
creas. Abnormal quantities of insulin are
produced with the result that the amount
of glucose in the blood can fall to dan-
gerously low levels (hypoglycaemia) and,
unless sugar is given immediately, can
cause comaand death. Once diagnosed, a
drug (diazoxide) is given to prevent hypo-
glycaemia until the tumour is removed.
intelligenceThe ability to understand
concepts and to reason them out. Intel-
ligence can also be considered as having
3 separate forms: abstract (understandingINSECURITY INTELLIGENCE
I